5. Atom can be defined as: (….) – The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons (except in the case of hydrogen-1, which is the only stable nuclide with no neutrons). The electrons of an atom are bound to the nucleus by the electromagnetic force.

6. Isotope can be defined as: (….) – An isotopein chemistry is an Atoms with the same number of protons, but differing numbers of neutrons. Isotopes are different forms of a single element. Isotope geochemistry is an aspect of geology based upon study of the relative and absolute concentrations of the elements and their isotopes in the Earth. Variations in the abundance of these isotopes, typically measured with an isotope ratio mass spectrometer or an accelerator mass spectrometer, can reveal information about the age of a rock or the source of air or water. Isotope ratios can even shed light on chemical processes in the atmosphere. Broadly, the field of isotope geochemistry is divided into two branches: stable and radiogenic isotope geochemistry.

7. Avogadro’s constant is: (….) – Avogadro’s Constant = 6.0221415 × 1023 mol-1 is defined as the ratio of the number of constituent particles N (usually atoms or molecules) in a sample to the amount of substance n (unit mole) through the relationship NA = N/n.[1] Thus, it is the proportionality factor that relates the molar mass of an entity, i.e., the mass per amount of substance, to the mass of said entity.[2]The Avogadro constant expresses the number of elementary entities per mole of substance and it has the value 6.02214129(27)×1023 mol−1.*2+*3+*4+Changes in the SI units are proposed that will change the constant to exactly 6.02214X×1023 when it is expressed in the unit mol−1.

8. A pencil lead composed mainly of:(….) – Pencil lead is made out of Graphite which is a lightweight substance composed mainly of carbon and clay.

9. Approximate temperature of absolute zero in degree centigrade is:(….). – (Absolute zero is the lowest possible temperature where nothing could be colder, and no heat energy remains in a substance. absolute zero is defined as precisely 0 K on the Kelvin scale and −273.15 on the Celsius (centigrade) scale and −459.67 degrees on the Fahrenheit scale.)

12. S.I unit of power is: (….) -The SI unit of power is the Watts (W).

13. The three colors used to make a color TV picture are:(….,…and….) – red, green, and blue.

14. Chemical composition of ozone: (….) – O3, or tri-oxygen.

15. The closest planet to the sun: (….) – The planet Mercury.

16. The mass of the electron is equal to the mass of the neutron.(….) – An electron has a mass that is approximately 1/1836 that of the proton. Mass of neutrons are greater than mass of electrons 1840 times

17. Boiling point of water in degree centigrade = (….) – 100°C, 212°F or 373.15 Kelvin.

18. Boiling point of water in Fahrenheit = (….) – (212 °F) at sea level.

19. Freezing point of water in degree centigrade = (….) – 0º is the freezing point of water in Celsius.

32. If I drop a mass of 1 Kg from rest vertically down, at what speed will it be travelling after 10 seconds? (ignore air resistance) Vf = Vi + g t • If I used a mass of 2 kg, will it fall faster? ( No) – Initial velocity (Vi) = 0

33. The half life of a radioactive material is: (….) – It is the period of time over which the number of radio active nuclei decreases by afactor of one half.

34. Does the half life time decreases or increases with increasing temperature? Temperature , pressure and volume not effect on half life.

35. A box contains 250 cm3 of a fluid with a mass of 260 kg (ignore the mass of the box) • Density = 1.04 g/ cm3 • Is the fluid oil or fresh water or salt water or gas? – Salt water.